Democratic U.S. Senator Mark Pryor, seeking a third term, is facing Republican U.S. Rep. Tom Cotton, an Iraq and Afghanistan war veteran who won a decisive victory for his House seat in 2012. Despite ad buys from partisans on both sides that have reached into the seven figures, polls show this race is still too close to call, and it hasn’t budged in months. Cotton and outside conservative groups have done their best to tie Pryor to Barack Obama and Nancy Pelosi, while Pryor and outside liberal groups have painted Cotton as a stooge of the Koch brothers and other moneyed special interests. Arkansas is a conservative state where Obama is monstrously unpopular, but it is also a state where local Democrats still hold most statewide offices. Pryor also benefits from a famous Arkansas political pedigree – his father, David, served as governor and U.S. senator.

This year’s U.S. Senate race in Georgia unusually features two major-party nominees who are making their political debut. However, Republican David Perdue and Democrat Michelle Nunn both hail from prominent Georgia political families. She is the daughter of former U.S. Senator Sam Nunn, while he is the cousin of former Governor Sonny Perdue. Despite the Peach State’s Republican tendencies, this is a race Democrats think they can win with Nunn, who benefits from not having been in Washington voting for Obamacare or other hot button issues. Perdue’s ultimate success or failure may depend on the degree to which he can link Nunn with national Democratic leaders in the minds of voters. But Nunn has an uphill climb in a state that hasn’t gone Democratic in a Senate race since 2000. And if the vote is close, another factor could come into play: Georgia, uniquely, has a general election runoff if no candidate crosses 50 percent, and there is a Libertarian in the race that could keep Nunn and Perdue below that threshold.

Democrats in the Bluegrass State have the top Republican in the Senate, Mitch McConnell, squarely in their cross-hairs, hoping to hand the GOP a major embarrassment by flipping this seat their way. McConnell bears the burdens of the electorate’s distaste for all things Congress and the aftermath of bruising primary battle. However, he won that primary rather easily against a more conservative and less experienced opponent, and he will be the majority leader if Republicans take the Senate – which, he is arguing, will be good for Kentucky. The Democrats nominated Alison Lundergan Grimes, a Lexington attornhey who was elected as secretary of state in 2010 at the tender age of 31. McConnell is 72 and has been in the Senate for 30 years, so this is clearly a race of youth against experience. But McConnell is known for his tenacity, and Grimes isn’t helped by the Obama administration’s unpopularity in Kentucky, particularly over its proposed limits on coal-fired electric plants.

Every six years, like clockwork, Louisiana Republicans try to knock off Democratic U.S. Senator Mary Landrieu, and, every six years, they fall short. But the GOP is hoping the fourth time will be the charm, particularly given Barack Obama’s popularity and Landrieu’s vote for Obamacare. She’s also run into a barrage of bad press over her use of Senate funds to fly to campaign appearances. Louisiana’s peculiar electoral process may also come into play in this race. All candidates from every party run in the November election, with the top two vote-getters meeting in a December 6 runoff if no one captures a majority – something that’s happened to Landrieu twice before. The leading Republican in the race is U.S. Rep. Bill Cassidy from Baton Rouge, who gave up his seat in the House to take on Landrieu. But also in the race is Rob Maness, a retired U.S. Air Force colonel and Tea Party favorite who have been endorsed by Sarah Palin, the Senate Conservatives Fund and the Family Research Council. If the Republicans capture a net of five of the six seats they need to take control and Landrieu can’t muster a majority, all eyes will be on the bayou come December.

A year ago, most folks in Mississippi thought this race would be a cakewalk for venerable U.S. Senator Thad Cochran, given his stature and the state’s staunch GOP nature. Then, State Senator Chris McDaniel jumped into the primary against him, and when it looked like McDaniel might actually knock off Cochran, former U.S. Rep. Travis Childers entered the fray, giving Democrats hope for a pick-up if McDaniel won. When neither Republican got a majority in the first round of primary voting, the race went to a runoff, which Cochran won by less than 7,700 votes after openly making appeals to Democratic and independent voters to cross-over and vote in the GOP runoff. That infuriated McDaniel’s supporters, and he went to court to overturn the result. The question for November is whether the bitter divisions in Republican ranks might give an opening to Childers in a state that hasn’t elected a Democrat to the Senate since 1982.

U.S. Senator Kay Hagan’s win over Elizabeth Dole was one of the biggest surprises of the 2008 election. Now, the freshman senator is coming up for re-election for the first time, and Republicans are going after her hard. Their nominee is State House Speaker Thom Tillis, who managed to win a hotly contested GOP primary without a runoff. In a state where regional voting often comes into play, she is from Greensboro, and he is from Charlotte. Hagan’s vote in favor of Obamacare has been front and center in attacks by Tillis and outside conservative groups that have been spending money in the Tar Heel State all year. But Democrats and Hagan have been going after Tillis over moves by the Republican-controlled state legislature, where he presides, to restrict abortion and require voters to present identification. North Carolina has become a swing state where small shifts in the electorate can mean the difference between winning and losing, so the enthusiasm of the base and the ground game could make the difference in November.

The race in Virginia pits popular Democratic U.S. Senator Mark Warner against Ed Gillespie, formerly a top political adviser to President George W. Bush and former chairman of the Republican National Committee. The late entry into the race of the politically savvy Gillespie has buoyed the Virginia GOP’s prospects in what had been seen as a Democratic lock. However, Barack Obama carried the commonwealth twice, an indication that the anti-Obama campaigns being run by Republicans across the South might not be as effective here. Warner has also raised more than $9 million and has his own multimillion-dollar fortune to dip into if the need arises. Though Gillespie got a late start, he’s raised more than $4 million, which should be enough to keep him within striking distance.

This seat opened up when Democratic U.S. Senator Jay Rockefeller decided to retire, and Republicans see West Virginia as their best chance to flip a seat anywhere in the South. GOP U.S. Rep. Shelley Moore Capito, who has represented a district in the central part of the state for the last 14 years, is trying to make her move up to the Senate. Democrats have nominated Secretary of State Natalie Tennant, a former television reporter who has served nearly six years in statewide office and whose claim to fame is that she was the first woman to ever serve as the Mountaineer mascot at West Virginia University. While Democrats still have a voter registration edge in West Virginia, which is also union country, Tennant has an uphill slog running as a Democrat in a state where Barack Obama is extremely unpopular. Tennant has been trying to put distance between herself and the Obama administration over new roles that would limit the use of coal in electric plants, but that may not be enough to surmount the mountain she has to climb.